Problem: Multiply. $4.9 \times 0.3 = $
Answer: $49 \times 3$ and $4.9 \times 0.3$ multiply the same digits in the same order. So, the product of both problems will also have the same digits in the same order. Let's multiply $49 \times 3$. Then we can estimate to place the decimal point in the product of $4.9 \times 0.3$. $\begin{aligned} 49&\\ \underline{ \times 3}&\\ 27}\\ \underline{+120}}\\ 147 \end{aligned}$ Let's estimate to place the decimal in $4.9 \times 0.3$. $\begin{aligned} 4.9 \times 0.3 &\approx 5 \times 0.3\\\\ &\approx \dfrac{5}{1}\times \dfrac{3}{10}\\\\ &\approx \dfrac{15}{10}\\\\ &\approx 1.5 \end{aligned}$ Where can we place the decimal in $147$ to get a product close to $1.5$ ? $4.9 \times 0.3 = 1.47$